Machining centers utilizing tool changer mechanisms can contribute significantly to improved flexibility and reduced non-cutting time in machining operations. Standardization of tool shanks and holders, as well as the use of modular tooling, interchangeable tool inserts, and uniform pallet sizes are the prerequisites. Both tooling and machine tool manufacturers are putting great effort into development of new systems designed to meet users requirements.
Machine centers are a relatively new development made possible by the versatility of numerically controlled machine tools, in particular the numerically controll lathe. However, tooling costs can account for a sizable portion of the total investment required to place a machining center in production. Typical tooling costs average 15-20% of the cost of the machining center. Thus, when several different machine tools are utilized in a production facility, minimization of the number of different tools becomes desirable and, for unattended production, mechanized tool handling becomes imperative. Stated in another manner, while tool standardization is welcome, optimum cutting performance mandates the use of specialized tool handling mechanisms that meet specific user requirements.
Numerically controlled turning has led to the grouping of several operations, thereby requiring the use of turrets with a multiplicity of tools. However, replacing worn tools or cutting inserts still materially adds to non-cutting time loss and is a primary obstacle to the utilization of unmanned machining centers. Therefore, a standarized tool system with hydraulically actuated tool change and storage thereof in a magazine which can be replenished at an operator's convenience is required to maximize the duration of unattended operation of the machine.